Computer and network systems such as personal computers, workstations, server systems, and cloud storage systems, typically include data storage systems for storing and retrieving data. These data storage systems can include data storage devices, such as phase change media devices, hard disk drives, solid state storage devices, tape storage devices, and other mass storage devices.
Phase change memory can be employed in various discrete phase change memory (PCM) devices or included in integrated circuit systems to store data in a computing system or storage system. For example, a motherboard or other circuit board of a computing or processing system can employ one or more phase change memory devices to store data related to the operation of the computing or processing system.
In examples of phase change storage media, such as phase change memory devices, phase change memory cells are employed to store data bits arrayed in chalcogenide glass material. These phase change memory cells can be changed from a crystalline state to an amorphous state, and vice versa, to store 1s and 0s associated with bits of data. The phase change storage media typically employs resistive heaters or a laser system to selectively heat individual phase change cells to change bits between the amorphous and crystalline states. The crystalline state typically requires a slower heating period than the amorphous state.
When data is written to or erased from a phase change memory device, the write or erase process can cause the phase change media to emit acoustic signals. These acoustic signals are typically correlated to the rapid change of physical state of the chalcogenide glass material, and can be on the order of microseconds for each written or erased bit. Unfortunately, these acoustic signals can lead to a less secure data environment by allowing for eavesdropping using ultrasonic acoustic pickup devices. For example, a microphone mounted in proximity to a phase change memory device might be able to monitor the data written to or erased from the phase change memory device.
Overview
To provide enhanced operation of phase change storage media associated with data storage devices, various systems, methods, and firmware are provided herein. In some examples, these systems, methods, and firmware can provide for data storage devices that include phase change media on which to write data, and a processing system configured to identify a write process to at least obfuscate an acoustic signature associated with writing the data on the phase change media and write the data to the phase change media in accordance with the write process. In further examples, the processing system is configured to identify an erase sequence to at least obfuscate an acoustic signature associated with erasing data on the phase change media, and erase the data on the phase change media in accordance with the erase sequence.